The Big Bang Theory

S12E12 - The Propagation Proposition

Penny's ex-boyfriend, Zack, and his wife want a baby, but when Zack is infertile, they ask Leonard for help. Also, Koothrappali attempts to mend things with his ex-fiancée, Anu.

Writer: |Chuck Lorre|Jeremy Howe|Maria Ferrari|Dave Goetsch|Steve Holland|Eric Kaplan|

The Big Bang Theory
S12E12